Japanese Patent Application Publication No. 2013-97151 discloses a process cartridge provided with a photosensitive drum and a developing roller. In the process cartridge, a residual toner remaining on the photosensitive drum is collected by the developing roller. Further, a cleaning unit is provided for collecting paper dust on the photosensitive drum in order to prevent or restrain the paper dust on the photosensitive drum from being collected by the developing roller.
More specifically, the cleaning unit includes a cleaning roller applied with a collection bias which can collect the paper dust without collecting the toner, and a pressure member positioned downstream of a transfer roller in a rotational direction of the photosensitive drum and in contact with the photosensitive drum for collecting the paper dust.